Qwen 3.5 122B MoE OC on a single 3090 at 35 t/s — full local stack breakdown
Summary
Detailed breakdown of running Qwen 3.5 122B MoE on a single RTX 3090 at 35 t/s using a custom llama.cpp fork (ik_llama.cpp) with fused MoE operations and expert offloading to CPU RAM, significantly outperforming stock llama.cpp MTP.
Similar Articles
EXPERIMENT: Qwen3.8-2.4T-A95B running locally on an RTX 5090 + RTX 5060 Ti at ~0.80 tok/s
An experiment running the Qwen3.8-2.4T-A95B MoE model locally on dual consumer GPUs (RTX 5090 + 5060 Ti) with llama.cpp, achieving ~0.8 tok/s with MTP speculative decoding enabled.
Qwen 3.8 Flash Next-GSQ-RCO-IQ2_XS at ~21 tok/s on just an RTX 3060 12GB + 16GB DDR4 RAM(No gate pruning, 100% bit-exact)
A developer showcases a custom `--moe-direct-io` feature for llama.cpp that achieves 10–15x speedup (20–24 tok/s) running the 125B MoE Qwen3.5-Flash Next (IQ2_XS, 68GB) on just an RTX 3060 12GB with 16GB RAM, while keeping output bit-exact to stock.
Qwen3.5-27B, Qwen3.5-122B, and Qwen3.6-35B on 4x RTX 3090 — MoEs struggle with strict global rules
A user benchmarks three Qwen models (Qwen3.5-27B dense, Qwen3.5-122B-A10B MoE, Qwen3.6-35B-A3B MoE) on 4x RTX 3090 GPUs under real agentic workloads, finding that MoE models consistently underperform the dense 27B at following strict global rules despite speed advantages, with the Qwen3.6-35B leading in generation throughput.
Qwen3.6-35B-A3B Q4 262k context on 8GB 3070 Ti = +30tps
The author shares detailed tuning tips for running the Qwen3.6-35B-A3B MoE model on an 8GB RTX 3070 Ti with up to 262k context using llama.cpp, achieving 30+ tps, and notes a 25% speed boost when switching from Windows to Ubuntu Server.
tandem.cpp: Qwen3.8-Flash-Next at 97 tok/s on a single 4090 + 64 GB RAM, 3.3× llama.cpp, works for any MoE
tandem.cpp is a patch set for llama.cpp that offloads MoE models overflowing VRAM by keeping hot experts on GPU while the CPU handles the rest, achieving 97.3 tok/s on a single RTX 4090 (3.3× faster than llama.cpp) for Qwen3.8-Flash-Next, with gains for other MoE models too.